I'm trying once more to get into electronics, meaning building as well as repairing things. During my research I've been surprised by the kind of components and projects that are available, although they seem to be obsolete technology, far older than classic Amigas. These projects include a crystal radio set and a Pong game console. Apart from these, people are able to get hold of components to make Sinclair Spectrum clones. These clones use compatible components, but now there's also an FPGA Spectrum clone. I know that various computers used graphics chips that had the same resolution (256x192?) as the Sinclair Spectrum.

Bearing all of this in mind, I can't understand the problems people are having getting hold of or making projects which are compatible with classic Amigas. I've now more or less given up on trying to get a hard drive which would fit my Amiga A500 Plus. It seems that not even Iomega Zip drives are compatible without a special interface. Surely, with enough electronics knowledge it should be possible to build a new Amiga hard drive controller and interface, as well as monitors which are compatible with classic Amigas without using a scandoubler or flicker fixer. Please will someone tell me what problems there would be doing either or these things?

BTW, later today I'll be going to an event where they do repairs, so I hope I'll find out some of this information there, but it won't be about the classic Amiga.

Bearing all of this in mind, I can't understand the problems people are having getting hold of or making projects which are compatible with classic Amigas.

Bruno,

I've spent years surveying parts that could be used to make a single board computer.  I could point you in the direction you want to go.  You might want to visit anycpu.org and chat with us.  

People who want to make a computer or a complex machine with chips don't always know what is involved.  Chips make what is hard simple and what you think is simple is sometimes hard.  Sometimes it isn't just about connecting the wires but it is about physics.

The problem is that manufacturers aren't going to make a part unless there is a market because products that don't sell means the manufacturer loses money.  Warehouses are afraid to stock a part unless it sells and they lose money when the customer changes his or her mind.

A lot of times you have to be an engineer to read a datasheet for a chip.  The datasheet for the processor in the Beaglebone is 2500+ pages long.  Some of the smaller chips have datasheets that are at least 300 pages long.  It takes some accomplished engineers a day to set up an ide.

Even people in the industry frown at the idea of making a single board computer because they know what it is like to make something and computers take many people to build.  If you were to write BASIC in a month, do you think the language would be extremely buggy?  Do you know anyone who can write a math package for a computer language?  It takes expertise, finess and a lot of love, time, willpower, illumination and inspiration to make a computer.

If I haven't discouraged you, visit anycpu.org and come and talk with us.

Chuck

Back in the Elder Days, I built a Z80 system from scratch... wire-wrapping all the boards... But I didn't design all of it, most of it came from plans in the hobbyist magazines of the time. (Kilobaud & Byte) But once I got it working, I kinda was scared off by realizing that I'd have to write an OS for it - or figure out how to port CP/M to it. So I went out and bought an Atari 800.  ;-)

You should check out places like Sparkfun or Adafruit. They have a lot off cool chips already soldered to breakout boards so you don't have to deal with those teeny packages. I've been wishing for a Zorro board with multiple SPI ports that could drive a bunch of those boards...

Surely, with enough electronics knowledge it should be possible to build a new Amiga hard drive controller and interface, as well as monitors which are compatible with classic Amigas without using a scandoubler or flicker fixer. Please will someone tell me what problems there would be doing either or these things?

Yes, with enough knowledge, time and money you can do practically anything.  The problem with the sorts of projects you mention, the knowledge required to do the job properly doesn't come overnight.  As others have mentioned, to design a drive controller from scratch, you need to have a thorough understanding of the interface to the Amiga and to the drive in order to both design the controller hardware plus the software on the Amiga side.  Then you need to look at physical construction, mounting, etc.

I've been electronics engineering for nearly 20 years and find it frequently annoying when people view any complex piece of electronics as something that can be whipped up by anyone holding a qualification to operate a light switch in five minutes by getting a few ICs and making a few random connections between them.  Every good design is generally the result of years of experience and hundreds if not thousands of hours of development and testing.

I tend to favour older technology in new designs because it's often easier to work with and requires less design work as you can re-use proven circuit blocks from previous designs.  e.g. 'modern' high speed logic can require complex design around signal propagation times, rise/fall times, PCB track lengths and more.

As an example, here's a design report from single board 8-bit embedded computer I designed from scratch a few years ago as an in-house universal production testing solution.  Many of the individual blocks were copied from previous projects and designs with the intention of reducing development time and cost as much as possible.  As a result the entire thing worked first time and met budget.  But it still took weeks of hand made prototype blocks, calculations, writing hardware interface software and a basic operating system.  See page 53 for how long it practically took and cost, and this is just a simple 8-bit embedded system reminiscent of what you'd see in the 1980s.

Here's the Pong console project I talked about http://www.mallinson-electrical.com/shop/build-your-own-retro-classic-pong-tv-video-game-project-kit-velleman-mk121-pal.html . How advanced is that technology?

The Raspberry Pi can play pong and can also be used for different things.

The Pong console will be thrown away when it gets dirty, dusty and when you are bored with it.  The pong console probably has a dedicated chip which can't be used for much else.

That pong kit is more of an assembly project rather than an electronics project that would teach you anything about electronics or require you to figure out what components you need.

I think the hardest part is making a vga ladder for video if you've never done video before.  

HDMI is probably more involved and knowing where to get the licensed chips and components.

Writing an operating system to be in tune with everything operating on the computer would be a challenge as well.

Bearing all of this in mind, I can't understand the problems people are having getting hold of or making projects which are compatible with classic Amigas. I've now more or less given up on trying to get a hard drive which would fit my Amiga A500 Plus. It seems that not even Iomega Zip drives are compatible without a special interface. Surely, with enough electronics knowledge it should be possible to build a new Amiga hard drive controller

I had a hard drive + 4MB ram expansion on my A500 in the 1989-1991 timeframe.  They were produced by multiple manufacturers and many thousands were sold.  Why didn't u buy one?

Stuff were incredibly expensive back then?

No it was super ridiculously cheap.

My A500 had 5 MEGABYTES of directly addressable ram + a hard drive.

My A2000 had 9 MEGABYTES of directly addressable ram + a ridiculous amount of HD storage.

And stereo DMA fed hardware double-buffered interrupt driven music.

And 32-bit multitasking.

Add up how much that cost to do on a Bill Gates compatible PC.  Around $8 billion (google translation: IMPOSSIBLE in 1989)

Now any price I paid was fantastically cheap.